#include "stdafx.h"
#include "CBase64.h"

namespace FaceCat{
	CBase64::CBase64(void){
	}
    
	CBase64::~CBase64(void){
	}
    
	string CBase64::encode(const unsigned char *Data,int DataByte){
		const char EncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
		string strEncode;
		unsigned char Tmp[4] = {0};
		int LineLength = 0;
		for(int i = 0;i < (int)(DataByte / 3); i++){
			Tmp[1] = *Data++;
			Tmp[2] = *Data++;
			Tmp[3] = *Data++;
			strEncode += EncodeTable[Tmp[1] >> 2];
			strEncode += EncodeTable[((Tmp[1] << 4) | (Tmp[2] >> 4)) & 0x3F];
			strEncode += EncodeTable[((Tmp[2] << 2) | (Tmp[3] >> 6)) & 0x3F];
			strEncode += EncodeTable[Tmp[3] & 0x3F];
			if(LineLength += 4,LineLength == 76) {strEncode += "\r\n"; LineLength=0;}
		}
		int Mod = DataByte % 3;
		if(Mod == 1){
			Tmp[1] = *Data++;
			strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
			strEncode += EncodeTable[((Tmp[1] & 0x03) << 4)];
			strEncode += "==";
		}
		else if(Mod==2){
			Tmp[1] = *Data++;
			Tmp[2] = *Data++;
			strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
			strEncode += EncodeTable[((Tmp[1] & 0x03) << 4) | ((Tmp[2] & 0xF0) >> 4)];
			strEncode += EncodeTable[((Tmp[2] & 0x0F) << 2)];
			strEncode += "=";
		}
		return strEncode;
	}
    
	string CBase64::decode(const char *Data,int DataByte,int& OutByte){
		const char DecodeTable[] =
		{
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			62,
			0, 0, 0,
			63,
			52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
			0, 0, 0, 0, 0, 0, 0,
			0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
			13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
			0, 0, 0, 0, 0, 0,
			26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
			39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
		};
		string strDecode;
		int nValue;
		int i= 0;
		while (i < DataByte){
			if (*Data != '\r' && *Data!='\n'){
				nValue = DecodeTable[*Data++] << 18;
				nValue += DecodeTable[*Data++] << 12;
				strDecode += (nValue & 0x00FF0000) >> 16;
				OutByte++;
				if (*Data != '='){
					nValue += DecodeTable[*Data++] << 6;
					strDecode += (nValue & 0x0000FF00) >> 8;
					OutByte++;
					if (*Data != '='){
						nValue += DecodeTable[*Data++];
						strDecode += nValue & 0x000000FF;
						OutByte++;
					}
				}
				i += 4;
			}
			else{
				Data++;
				i++;
			}
		}
		return strDecode;
	}  
}
